The appearance of multiple pigmented light-brown, smooth-edged skin lesions measuring less than 2 centimeters could be consistent with:

Rationale: A. Mongolian spots are usually blue-gray, congenital, and most often found on the sacral or buttock area in newborns; they are not light-brown with smooth edges. B. Erythema toxicum presents as red, blotchy macules or papules with a yellow-white center and typically appears in the first few days of life; they are not light-brown pigmented lesions. C. Café-au-lait spots are light-brown, smooth-edged, round or oval macules that can vary in size but are usually under 2 cm in younger children. Multiple café-au-lait spots can be associated with neurofibromatosis type 1 if six or more are present. D. Congenital ichthyosis manifests as generalized scaling or thickened skin, not as discrete pigmented macules.